Block copolymers with acidic groups

ABSTRACT

Block copolymer that can be formed into an ion-conductive membrane are provided. The block copolymer of the invention includes a first polymer block and a second polymer block attached to the first polymer block. The first polymer block has a main polymer chain and one or more side chains extending from the main polymer chain. The one or more side chains include at least one substituent for proton transfer. Block copolymers utilizing phosphoric acid groups are also provided.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to block copolymers that can be formedinto ion conductive membranes for fuel cell applications.

2. Background Art

Fuel cells are used as an electrical power source in many applications.In particular, fuel cells are proposed for use in automobiles to replaceinternal combustion engines. In proton exchange membrane (“PEM”) typefuel cells, hydrogen is supplied to the anode of the fuel cell andoxygen is supplied as the oxidant to the cathode. The oxygen can beeither in a pure form (O₂) or air (a mixture of O₂ and N₂). PEM fuelcells typically have a membrane electrode assembly (“MEA”) in which asolid polymer membrane has an anode catalyst on one face and a cathodecatalyst on the opposite face.

The MEA, in turn, is sandwiched between a pair of non-porous,electrically conductive elements or plates which (1) serve as currentcollectors for the anode and cathode, and (2) contain appropriatechannels and/or openings formed therein for distributing the fuel cell'sgaseous reactants over the surfaces of the respective anode and cathodecatalysts.

In order to efficiently produce electricity, the polymer electrolytemembrane of a PEM fuel cell typically, must be thin, chemically stable,proton transmissive, non-electrically conductive, and gas impermeable.Moreover, during operation of the fuel cell, the PEM is exposed torather severe conditions, which include, hydrolysis, oxidation andreduction (hydrogenation) that can lead to degradation of the polymerthereby reducing the lifetime of a polymer electrolyte membrane. Thecombination of these requirements imposes rather strict limitations onmaterial choices for these membranes. Presently, there are relativelyfew polymer systems that provide even marginally acceptable results forthe combination of these requirements. An example of a PEM is the Nafionmembrane developed by DuPont in 1966 as a proton conductive membrane.This membrane is possibly the only advanced polymer electrolytecurrently available for use in a membrane electrode assembly in a fuelcell.

Other polymer systems that may be used in PEM applications are found inU.S. Pat. No. 4,625,000 (the '000 patent), U.S. Pat. No. 6,090,895 (the'895 patent), and EP Patent No. 1,113,517 A2 (the '517 patent). The '000discloses a sulfonation procedure forming poly(ether sulfone)s that maybe used in solid polymer electrolyte application. However, the '000patent's post-sulfonation of preformed polymers offers little control ofthe position, number, and distribution of the sulfonic acid groups alongthe polymer backbone. Moreover, the water uptake of membranes preparedfrom post sulfonated polymers increases, leading to large dimensionalchanges as well as a reduction in strength as the degree of sulfonationincreases.

The '895 patent discloses a process for making cross linked acidicpolymers of sulfonated poly(ether ketone)s, sulfonated poly(ethersulfone)s, sulfonated polystyrenes, and other acidic polymers by crosslinking with a species which generates an acidic functionality. However,this reference does not suggest an effective way to cast membranes fromthose cross linked sulfo-pendent aromatic polyethers.

The '517 patent discloses a polymer electrolyte containing a blockcopolymer comprising blocks having sulfonic acid groups and blockshaving no sulfonic acid groups formed by post sulfonation of precursorblock copolymers consisting of aliphatic and aromatic blocks. In thispatent, the precursor block copolymers are sulfonated using concentratedsulfuric acid, which leads to the sulfonation of aromatic blocks.However, once again, this post sulfonation of aromatic blocks offers thelittle control of the position, number, and distribution of the sulfonicacid groups along the polymer backbone. Furthermore, this postsulfonation of precursor block copolymers also leads to the cleavage ofchemical bonds of the aliphatic block.

Although some of the proton conducting membranes of the prior artfunction adequately in hydrogen fuel cells, these membranes tend torequire high humidity (up to 100% relative humidity) for efficientlong-term operation. Moreover, prior art membranes are not able toefficiently operate at temperatures above 80° C. for extended periods oftime. This temperature limitation necessitates that these membranes beconstantly cooled and that the fuel (i.e., hydrogen) and oxidant behumidified.

Accordingly, there exists a need for improved materials for formingpolymer electrolyte membranes and for methods of forming such materials.

SUMMARY OF THE INVENTION

The present invention overcomes the problems encountered in the priorart by providing in one embodiment a block copolymer that can be formedinto an ion-conductive membrane. The block copolymer of this embodimentis characterized by having alternating hydrophobic and hydrophilicpolymer blocks. Specifically, the block copolymer of this embodimentincludes a first polymer block (i.e., a hydrophobic polymer block) and asecond polymer block (i.e., a hydrophilic polymer block) attached to thefirst polymer block. The first polymer block has a main polymer chainand one or more side chains extending from the main polymer chain (i.e.,spacers). The one or more side chains include at least one substituentfor proton transfer. Typically, the substituent for proton transfer isan acid group or a salt of an acid group. The presence of these acidicgroups on spacers within the hydrophilic segments allows the acidicgroups to arrange themselves in orientations suitable for protondissociation at low water levels through neighbour-group interactions.

In another embodiment of the invention, an ion conducting membraneincorporating the block copolymers of the invention is provided. The ionconducting membrane is advantageously useable in a fuel cell, and in atleast one embodiment, a hydrogen fuel cell, operating continuously attemperatures up to about 120° C.

Membranes formed from the block copolymers of the invention arecharacterized by having a microphase separated morphology due to thealternating hydrophobic and hydrophilic polymer sequences. Moreover, theion conducting membranes of this embodiment have higher protonconductivities at low relative humidities than random copolymers ofsimilar composition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides plots that compare specific conductivities vs. relativehumidity at 80° C.: diamonds correspond to block (sulfonated poly(ethersulfone) block copolymers with sulfonation on the main chain (Example 1with an IEC=1.8); circles correspond to a block copolymer withsulfonation on the side chain (Example 2 having an IEC=1.7); andtriangles correspond to a block copolymer with sulfonation on the mainchain and side chains (Example 3 having an IEC=2.5); and

FIG. 2 provides plots that compare specific conductivities vs. relativehumidity at 80° C. for various sulfonated poly(ether sulfone)s thatinclude literature data for random sulfonation (squares, IEC=2.48) and ablock copolymer with side chain sulfonation (circles, Example 2 havingan IEC=2.5).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Reference will now be made in detail to presently preferred compositionsor embodiments and methods of the invention, which constitute the bestmodes of practicing the invention presently known to the inventors.

The term “block” as used herein means a portion of a macromolecule,comprising many constitutional units, that has at least one feature thatis not present in adjacent portions.

The term “block macromolecule” as used herein means a macromolecule thatis composed of blocks in linear sequence.

The term “block polymer” as used herein means a substance composed ofblock macromolecules.

The term “block copolymer” as used herein means a polymer in whichadjacent blocks are constitutionally different, i.e., each of theseblocks comprise constitutional units derived from differentcharacteristic species of monomer or with different composition orsequence distribution of constitutional units.

The term “random copolymer” as used herein means a copolymer consistingof macromolecules in which the probability of finding a given repeatingunit at any given site in the chain is independent of the nature of theadjacent units.

In one embodiment, the present invention provides a block copolymer thatcan be formed into an ion-conductive membrane. In particular, blockcopolymers of the invention are particularly useful for forming ionconductive membranes to be used in PEM fuel cells. The block copolymersof the invention are characterized by having a sequence of alternatinghydrophobic and hydrophilic blocks. These alternating segments areimmiscible thereby inducing a microphase separated morphology in filmscast from these materials. The block copolymer of the invention includesa first polymer block and a second polymer block attached to the firstpolymer block. The first polymer block has a main polymer chain and oneor more side chains (i.e., spacers) extending from the main polymerchain. Each of the one or more side chains include at least onesubstituent for proton transfer.

In an embodiment of the invention, a block copolymer for use as a solidpolymer electrolyte is provided. The block copolymer of this embodimentcomprises a polymer having formula 1:(A_(m)B_(n)) _(p)   1wherein

A is a first polymer segment that is repeated m times to form firstpolymer block A_(m);

B is a second polymer segment that is repeated n times to form secondpolymer block B_(n), and

m, n, p are each independently an integer.

Significantly, the second polymer segment has a main polymer chain andone or more side chains extending from the main polymer chain. Each ofthe side chains includes at least one substituent for proton transfer.First polymer block A_(m) is bonded to second polymer block B_(n). Ithas been discovered that the block copolymer of this embodiment isformable into an ion-conductive membrane that is useful for fuel cellapplications, and in particular, for fuel cells operating attemperatures as high as 120° C. In a particularly useful variation, m, nare each independently an integer from 1 to 200 and p is an integer from1 to 20.

Second polymer segment B includes at least one substituent for protontransfer. In a variation of this embodiment, such substituents forproton transfer include acidic substituents and salts thereof. Salts inthis context are salts of the conjugate bases to an acidic substituent.Examples of suitable substituents for proton transfer are sulfonic andphosphonic acid groups and salts thereof which include, but are notlimited to, —SO₃H, —SO₃ ⁻M⁺, —COOH, —COO⁻M⁺, —PO₃H₂, —PO₃H—M⁺, —PO₃ ²⁻M₂⁺, —PO₃ ²⁻M²⁺, and combinations thereof. In these examples, M is a metalsuch as an alkali or alkaline-earth metal, ammonium, or alkylammonium.Particularly useful metals are sodium, potassium, lithium, and the like.

In a variation of the invention, the first block Am has a molecularweight from about 5×10² to about 5×10⁵ (g/mol) and the second polymerblock B_(n) has a molecular weight from about 5×10² to about 5×10⁵(g/mol). Moreover, the present embodiment is further characterized inthat the first polymer block A_(n) is hydrophobic and the second polymerblock B_(n) is hydrophilic. For example, when B_(n) is hydrophilic, Bdescribed by formula 2:

wherein:

Y¹ is —O—, —S—, —CO—, —SO₂—, —C(CH₃)₂—, —C(CF₃)₂—, —P(O)(R⁴)—,—C(CH₃)(T¹)-, —P(O)(R⁴)—, diphenyl methylene, diphenyl silicon,fluorenyl, an alkylene, a bond directly to the next aromatic ring, or

R¹, R², and R³ are each independently H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl,C₆₋₁₈aralkyl, SO₃H, —SO₃ ⁻M⁺, —COOH, —COO⁻M⁺, —PO₃H₂, —PO₃H⁻M₊, or —PO₃²⁻M₂ ⁺, —PO₃ ²⁻M²⁺;

R⁴ is H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl, or C₆₋₁₈ aralkyl;

T¹ is H or a moiety having at least one substituent for proton transferincluding for example formula 3 set forth below; and

i is an integer from 1 to 6.

The polymer segment having formula 2 is further limited with the provisothat when i>1, the Y¹ between sequential aromatic rings are the same ordifferent; the T¹ on sequential aromatic rings are the same ordifferent; the R¹, R², and R³ on sequential aromatic rings are the sameor different; and T¹ is a moiety having at least one substituent forproton transfer for at least one aromatic ring in B. Suitablesubstituents for proton transfer include SO₃H, —SO₃ ⁻M⁺, —COOH, —COO⁻M⁺,—PO₃H₂, —PO₃H⁻M⁺, or —PO₃ ²⁻M₂ ⁺, —PO₃ ² ⁻M²⁺ as defined above. Thepresence of a phosphonic acid group or related salt (i.e., —PO₃H₂,—PO₃H⁻M⁺, —PO₃ ²⁻M₂ ⁺, or —PO₃ ² ⁻M²⁺) is particularly useful in T¹ orin R¹, R², and R³. Since phosphonic acid is a dibasic acid with a weaklydissociating second acid group, an alternative mechanism for protontransport, which is not possible in monobasic acids such as sulfonicacid, is available. Moreover, this mechanism is expected to operate evenat low water contents than when monobasic acids are used. Accordingly,such polymers exhibit higher proton conductivity at lower humidity andwater content than polymers of similar structure with sulfonic acidgroups. Although the beneficial effects of using phosphonic acid groupsare not limited to any particular mechanism, the proton transportmechanism in the presence of phosphonic acid groups is believed to be aGrotthus mechanism that operates through chains of hydrogen bondsthereby requiring a non-dissociated group. In a variation of thisembodiment, at least one of R¹, R², and R³ is —PO₃H₂, —PO₃H⁻M⁺, —PO₃²⁻M₂ ⁺, or —PO₃ ²⁻M²⁺.

In a particularly useful variation of this embodiment, T¹ is describedby formula 3:

wherein:

Y² is —O—, —S—, —CO—, —SO₂—, —C(CH₃)₂—, —C(CF₃)₂—, —P(O)(R⁴)—, diphenylmethylene, diphenyl silicon, fluorenyl, an alkylene, or a bond directlyto the next aromatic ring;

R⁴ is H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl, or C₆₋₁₈ aralkyl;

R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², and R¹³ are each independently H,C₁₋₁₀ alkyl, C₆₋₁₈ aryl, C₆₋₁₈ aralkyl, SO₃H, —SO₃ ⁻M⁺, —COOH, —COO⁻M⁺,—PO₃H₂, —PO₃H⁻M⁺, —PO₃ ²⁻M₂ ⁺, or —PO₃ ²⁻M²⁺;

M is a metal, ammonium, or alkylamonium; and

j is an integer from 1 to 30.

The spacer having formula 3 is further limited by the proviso that whenj>1, the Y² between sequential aromatic rings are the same or different;the R⁵, R⁶, R⁷, R⁸, and R⁹ on sequential aromatic rings are the same ordifferent; and at least one of R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², andR¹³ is —SO₃H, —SO₃ ⁻M⁺, —COOH, —COO⁻M⁺, —PO₃H₂, —PO₃H⁻M⁺, —PO₃ ²⁻M₂ ⁺,or —PO₃ ²⁻M²⁺.

Similarly, examples of hydrophobic polymer segment A are described byformula 4:

wherein:

Y³ is —O—, —S—, —CO—, —SO₂—, —C(CH₃)₂—, —C(CF₃)₂—, —P(O)(T¹)-,—C(CH₃)(T¹)-, —P(O)(R⁴)—, diphenyl methylene, diphenyl silicon,fluorenyl, an alkylene, a bond directly to the next aromatic ring, or

R⁴ is H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl, or C₆₋₁₈ aralkyl;

T¹ is H or a moiety having at least on substituent for proton transferas set forth above; and

R¹⁴, R¹⁵, R¹⁶, and R¹⁷ are each independently H, C₁₋₁₈ alkyl, C₆₋₁₈aryl, or C₆₋₁₈ aralkyl;

k is an integer from 1 to 6.

Polymer segment having formula 4 is further limited by the proviso thatwhen k>1, the Y³ between sequential aromatic rings are the same ordifferent and the R¹⁴, R¹⁵, R¹⁶, and R¹⁷ on sequential aromatic ringsare the same or different.

As set forth above, formula 2 provides examples of hydrophilic blocks.Specific examples when B is hydrophilic are given by formulae 5 through12 and salts thereof:

As set forth above, formula 4 provides examples of hydrophobic blocks.Specific examples when A is hydrophobic are provided by formulae 13through 16 and salts thereof:

In another embodiment of the invention, a block copolymer for use as asolid polymer electrolyte is provided. The copolymer of this embodimentis described by formula 1:(A_(m)B_(n))_(p)   1wherein A is a first polymer segment described by formula 4:

B is a second polymer segment described by formula 2:

Y¹ and Y³ are each independently —O—, —S—, —CO—, —SO₂—, —C(CH₃)₂—,—C(CF₃)₂—, —P(O)(T¹)-, —C(CH₃)(T¹)-, —P(O)(R⁴)—, diphenyl methylene,diphenyl silicon, fluorenyl, an alkylene, a bond directly to the nextaromatic ring, or

R¹, R², and R³ are each independently H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl, C₆₋₁₈aralkyl, SO₃H, —SO³⁻M⁺, —COOH, —COO⁻M⁺, —PO₃H₂, —PO₃H⁻M⁺, —PO₃ ²⁻M₂ ⁺,or —PO₃ ²⁻M²⁺;

R⁴ is H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl, or C₆₋₁₈ aralkyl;

M is a metal, ammonium, or alkylamonium;

R¹⁴, R¹⁵, R¹⁶, and R¹⁷ are each independently H, C₁₋₁₈ alkyl, C₆₋₁₈aryl, or C₆₋₁₈ aralkyl;

T¹ is H or a moiety having at least one substituent for proton transferas set forth above;

m, n, p are each independently an integer;

i is an integer from 1 to 6; and

k is an integer from 1 to 6.The polymer segment described by formula 2 is further limited by theproviso that when i>1, the Y¹ between sequential aromatic rings are thesame or different; the T¹ on sequential aromatic rings are the same ordifferent; and the R¹, R², and R³ on sequential aromatic rings are thesame or different. Moreover, for at least one aromatic ring in formula2, either T¹ is not H or one of R¹, R², or R³ is —SO₃H, —SO₃ ⁻M⁺, —COOH,—COO⁻M⁺, —PO₃H₂, —PO₃H⁻M⁺, —PO₃ ²⁻M₂ ⁺, or —PO₃ ²⁻M²⁺. The polymersegment described by formula 4 is similarly limited by the proviso thatwhen k>1, the Y³ between sequential aromatic rings are the same ordifferent and the R¹⁴, R¹⁵, R¹⁶, and R¹⁷ on sequential aromatic ringsare the same or different. In a particularly useful variation of thisembodiment, m, n are each independently an integer from 1 to 200 and pis an integer from about 1 to 20. Moreover, a particularly usefulexample of T¹ is described by formula 3:

wherein:

Y² is —O—, —S—, —CO—, —SO₂—, —C(CH₃)₂—, —C(CF₃)₂—, —P(O)(R⁴)—, diphenylmethylene, diphenyl silicon, fluorenyl, an alkylene, or a bond directlyto the next aromatic ring;

R⁴ is H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl, or C₆₋₁₈ aralkyl;

R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², and R¹³ are each independently H,C₁₋₁₀ alkyl, C₆₋₁₈ aryl, C₆₋₁₈ aralkyl, SO₃H, —SO³⁻M⁺, —COOH, —COO⁻M⁺,—PO₃H₂, —PO₃H⁻M⁺, PO₃ ²⁻M₂ ⁺, or —PO₃ ²⁻M²⁺;

M is a metal, ammonium, or alkylamonium; and

j is an integer from 1 to 30.

Side chain having formula 3 is further limited by the proviso that whenj>1, the Y² between sequential aromatic rings are the same or differentand the R⁵, R⁶, R⁷, R⁸, and R⁹ on sequential aromatic rings are the sameor different. Moreover, at least one of R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹,R¹², and R¹³ is —SO₃H, —SO₃ ⁻M⁺, —COOH, —COO⁻M⁺, —PO₃H₂, —PO₃H⁻M⁺, —PO₃²⁻M₂ ⁺, or —PO₃ ²⁻M²⁺. In a variation of this embodiment, R¹, R², and R³are each independently H, —PO₃H₂, —PO₃H⁻M⁺, —PO₃ ²⁻M₂ ⁺, or —PO₃ ²⁻M²⁺;and T¹ is H.

In another embodiment of the invention, a block copolymer having formula1 is provided:(A_(m)B_(n))_(p)   1wherein:

A is a first polymer segment;

B is a second polymer segment described by formula 17:

m, n, p are each independently an integer;

R¹⁹, R²⁰, R²¹, R²², R²³, R₂₄, R²⁵, R²⁶, R₂₇, R²⁸, R²⁹, R³⁰, R³¹, R³²,R³³, and R³⁴ are each independently H, —SO₃H, —SO₃ ⁻M⁺, —COOH, —COO⁻M⁺,—PO₃H₂, —PO₃H⁻M⁺, —PO₃ ²⁻M₂ ⁺, or —PO₃ ²⁻M²⁺; and

M is a metal, ammonium, or alkylammonium.

In a particularly useful variation of this embodiment, m, n are eachindependently an integer from 1 to 200 and p is an integer from 1 to 20.In another particularly useful variation of this embodiment, A isdescribed by formula 4:

Y³ is —O—, —S—, —CO—, —SO₂—, —C(CH₃)₂—, —C(CF₃)₂—, —P(O)(T¹)-,—C(CH₃)(T¹)-, —P(O)(R⁴)—, diphenyl methylene, diphenyl silicon,fluorenyl, an alkylene, a bond directly to the next aromatic ring, or

R⁴ is H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl, or C₆₋₁₈ aralkyl;

T¹ is H or a moiety having at least one substituent for proton transferas set forth above;

R¹⁴, R₁₅, R¹⁶, and R¹⁷ are each independently H, C₁₋₁₈ alkyl, C₆₋₁₈aryl, or C₆₋₁₈ aralkyl; and

k is an integer from 1 to 6.

The polymer segment B described by formula 4 is further limited by theproviso that when k>1, the Y³ between sequential aromatic rings are thesame or different; and the R¹⁴, R¹⁵, R¹⁶, and R¹⁷ on sequential aromaticrings are the same or different.

In another embodiment of the invention, the block copolymers set forthabove are used to form an ion conductive membrane. As set forth above,the block copolymers of the invention are characterized by havingalternating hydrophobic and hydrophilic polymer blocks that induce amicrophase separated morphology when the polymers are formed into films.Due to this microphase separated morphology, the polymer segments withacidic groups are associated in hydrophilic domains that containessentially no hydrophobic segments. Moreover, the local concentrationof acidic groups in the hydrophobic domains is higher than in a randomlysulfonated polymer such as SPEEK. Also, water taken up by membranes willbe present only in the hydrophilic domains and not in hydrophobicdomains. Therefore, at a given overall IEC value and water content, theblock copolymers will contain a higher local IEC and water level withinthe hydrophilic domains than compared to random copolymers. Themicrophase separated morphology includes, for example, morphologies suchas spheres, cylinders, lamellae, ordered bi-continuous double diamondstructures, and combinations thereof.

The method of making such membranes begins first with preparation of theblock copolymers of the present invention. In a variation of theinvention a first polymer having formula 18 is prepared:

wherein Z₁ and Z₂ are each independently —SH, —S(O)N(R¹⁸)₂, F, Cl, Br,I, —NO₂, or —OH; and R¹⁸. is H, C₁₋₁₀ alkyl, cycloalkyl, C₆₋₁₈ aryl, orC₆₋₁₈ aralkyl; and T¹, R¹, R², R³, Y¹ and i are the same as set forthabove. Similarly, an end functionalized second polymer block havingformula 19 is also synthesized:

wherein Z³ and Z⁴ are each independently —H, —SH, —S(O)N(R¹⁸)₂, F, Cl,Br, I, —NO₂, or —OH; and R¹⁸ is H, C₁₋₁₀ alkyl, cycloalkyl, C₆₋₁₈ aryl,or C₆₋₁₈ aralkyl; and R¹⁴, R¹⁵, R¹⁶, R¹⁷, Y³, and k are the same asthose set forth above. The block copolymers in at least some embodimentsof the invention are then prepared by reacting polymer block 18 withpolymer block 19.

In another variation of the invention, the polymer block having formula19 is reacted with one or more monomers suitable for forming the polymerblock having formula 18. Specifically, the block copolymers of theinvention having formula 1 are prepared by synthesizing anend-functionalized polymer block having formula 19:

wherein R¹⁴, R¹⁵, R¹⁶, R¹⁷, Y³, and k are the same as set forth above;Z³ and Z⁴ are each independently —H, —SH, —S(O)N(R¹⁸)₂, F, Cl, Br, I,—NO₂, or —OH; and

-   R¹⁸ is H, C₁₋₁₀ alkyl, cycloalkyl, C₆₋₁₈ aryl, or C₆₋₁₈ aralkyl. In    this embodiment, the polymer block having formula 21 is then reacted    with one or more monomers that polymerize into a block having    formula 2:    to form the block copolymer having formula 1, wherein R¹, R², R³,    Y¹, T¹ and i are the same as set forth above.

In yet another variation of this embodiment, the polymer block havingformula 18 is reacted with one or more monomers suitable for forming thepolymer block having formula 19. Specifically, the block copolymers inat least some embodiments of the invention are formed by synthesizing anend-functionalized polymer block having formula 18:

wherein R¹, R², R³, Y¹, T¹, and i are the same as set forth above; Z¹and Z² are each independently —H, —SH, —S(O)N(R¹⁸)₂, F, Cl, Br, I, —NO₂,or —OH; and

-   R¹⁸ is H, C₁₋₁₀ alkyl, cycloalkyl, C₆₋₁₈ aryl, or C₆₋₁₈ aralkyl. In    the embodiment, the polymer block having formula 18 is then reacted    with one or more monomers that polymerize into a block having    formula 4:    to form the block copolymer having formula 1, wherein R¹⁴, R¹⁵, R¹⁶,    R¹⁷, Y³, and k are the same as set forth above.

In an example of the preparation of the block copolymer of at least someembodiments of the invention, hydrophobic block 19 is synthesized usingone or more non-sulfonated bis-functional monomers. Such bis-functionalmonomer typically includes two groups that are halogens (F, Cl, Br, I)and OH. The molecular mass (i.e. which is proportional to the number ofrepeating units) of the block is adjusted by using a definedstoichiometric ratio between the difunctional monomers preferably in therange of 1:2 to 200:1. After the reaction is completed the hydrophobicblock is isolated by precipitation in a solvent such as methanol. Nextthe hydrophobic block is washed with excess amounts of the solvent(i.e., methanol) and subsequently with water. The dried hydrophobicblock is used for the preparation of the multiblock copolymer togetherwith the sulfonated monomers. Next, the dried hydrophobic first block isreacted with one or more monomers that includes at least one substituentfor proton transfer. In one variation, the monomer that includes atleast one substituent for proton transfer is on a side chain as setforth above. In another variation, the monomer that includes at leastone substituent for proton transfer is a —PO₃H₂, —PO₃H⁻M+, —PO₃ ²⁻M₂ ⁺,or —PO₃ ²⁻M²⁺. Optionally, one or more additional bis-functionalmonomers that may or may not include substituents for proton transferare also reacted with the monomer that does include a substituent forproton transfer. In at least one embodiment, in order to adjust thecomposition of the multiblock copolymer the necessary ratio between themonomers building the hydrophilic block and the hydrophobic block isused. The polymer is isolated by precipitation and purified in the samemanner by precipitation into alcohol as for the hydrophobic blocks butwithout washing with water since the multiblocks especially when havinga large hydrophilic block swell when in contact with water which resultsin difficulties in filtering the polymer. The resulting polymer flakesare thoroughly dried.

Regardless of the method by which the block copolymers of the inventionare formed, the block copolymers are eventually formed or cast into anion conductive membrane suitable for fuel cell applications. The polymercan be cast from solution in its acid, acid halide or salt form. Inaddition, a membrane can also be formed by hot pressing or by meltextrusion of the polymer. The behavior of the polymer during hotpressing or during melt extrusion can be improved by transferring theacidic groups:in the polymer into ester groups or other protectivegroups, which can be returned into acid groups after melt processing. Inone variation, the acid groups of the block copolymer are transformed toacid halide groups to form a modified block copolymer. Then a film iscast from a solution of the modified block copolymer onto a substrate.Finally, the acid halide groups are transformed back into the acidgroups to form the ion conductive membrane. After formation of themultiblock copolymers of the present invention, ion conductive membranescan be formed. In a first refinement of this embodiment, the driedpolymer is dissolved in a suitable solvent (i.e., DMSO). The polymersolution is then poured into a Petri dish and is covered with a lid insuch a way that there is a small gap between the dish and the lid toallow for slow evaporation of the solvent. In another refinement, thedried polymer is also dissolved in a suitable solvent to form a viscoussolution. The viscous solution is spread onto a glass plate and broughtto a uniform thickness by means of a doctor blade. For both theserefinements, the solvent is then removed by drying at elevatedtemperature in an oven. Finally, the morphology is adjusted by annealingthe membrane at an elevated temperature. Typically, this annealing isperformed at reduced pressures or in a vacuum. Useful annealingtemperatures are either between the glass transition or meltingtemperatures of the two block types, or between the highest of the glassstransition or melt temperatures of the two block types and theorder-disorder transition temperature (if present). Temperatures betweenabout 100° C. and 300° C. are useful with an optimal anneal temperaturebeing about 200° C. In some variations of the invention, the afterpolycondensation steps, the multiblock copolymer of the invention isobtained a sulfonic acid salt or phosphorus acid salt. Therefore themembrane is converted into its free sulfonic acid form prior to use.This conversion is accomplished by containing the membranes with adiluted acid (e. g. 1 molar sulfuric acid) for 24 hours. Afterwards themembranes are rinsed thoroughly with DI water to remove excessive acid.

Ion conducting membranes formed by the polymers set forth in theexamples can be characterized by the ion exchange capacity (“IEC”),water uptake, and specific conductivity.

1. Determination of the IEC by Titration:

Membrane pieces in the sulfonic acid form are dried at 120° C. andvacuum for at least 2 hours. About 100 mg of the polymer and 50 ml ofaqueous LiCl solution with a concentration of 2 mol/l are put into anErlenmeyer flask with a cover. The closed flask is placed in an oven at60° C. over night for the cation exchange. The solution is cooled downto room temperature and three drops of a 0.5 wt. % ethanolicphenolphthalein solution are added as an indicator. The solutionincluding the membrane pieces are titrated with a sodium hydroxidesolution having a concentration of 0.1008 mol/l until the firstincidence of a pink coloration. If the color fades after 30 seconds,additional drops of the sodium hydroxide solution are added until thepink color persists. The IEC is calculated according to the followingequation (V(NaOH) is volume of the NaOH solution and c(NaOH) is theconcentration of the NaOH solution:${{IEC}\left\lbrack {{meq}\text{/}g} \right\rbrack} = \frac{{{c({NaOH})}\left\lbrack {{mol}\text{/}l} \right\rbrack} \cdot {{V({NaOH})}\quad\lbrack{ml}\rbrack}}{{m\left( {{dry}\quad{polymer}} \right)}\quad\lbrack g\rbrack}$The titration is repeated 5 times for each polymer analyzed.2. Determination of the Water Uptake

Membrane pieces with a size of about 1 cm² are placed in water at a 5predetermined temperature and equilibrated for several hours. The wetmembrane pieces are padded dry with a paper wipe and weighed with abalance having an accuracy of ±1 μg. The water uptake is calculatedaccording to the following equation:${{water}\quad{{uptake}\quad\lbrack\%\rbrack}} = {\frac{\begin{matrix}{{{m\left( {{wet}\quad{polymer}} \right)}\quad\lbrack{mg}\rbrack} -} \\{{m\left( {{dry}\quad{polymer}} \right)}\quad\lbrack{mg}\rbrack}\end{matrix}}{{m\left( {{dry}\quad{polymer}} \right)}\quad\lbrack{mg}\rbrack} \cdot 100}$The measurement is conducted with five pieces for each polymer analyzed.3. Measurement of the Specific Conductivity:

The specific conductivity measurements are conducted at differenttemperatures and different relative humidities or in water at differenttemperatures. The analyzed membranes are in the sulfonic acid form. Theimpedance is measured with a 4-probe setup. Specifically, ACmeasurements are carried out at a fixed frequency of 1 kHz with a FlukeRCL meter PM6304. The specific conductivity can be calculated accordingto the following equation:${\sigma\left\lbrack {S\text{/}{cm}} \right\rbrack} = {{\frac{1}{Z}\frac{l_{SE}}{w_{M} \cdot t_{M}}} = \frac{200}{{Z\left\lbrack {k\quad\Omega} \right\rbrack} \cdot {w_{M}\lbrack{mm}\rbrack} \cdot {t_{M}\left\lbrack {\mu\quad m} \right\rbrack}}}$where W_(M) is the width and t_(M) the thickness of the membrane andI_(SE) is the distance between the two sensor electrodes which is fixedat 20 mm for this sample holder. A Teflon cap is placed on top of themembrane by pressing the membrane with a clamp.4. Measurement Conditions

a. In Water

Measurements in water are performed by first equilibrating the membranesample in water to ensure that the sample is at a uniform temperature. Auniform temperature is necessary because clamping of the membraneagainst the electrodes in the sample holder the measurement would beinaccurate if the membrane does not swell homogenously in all directionsat elevated temperatures. The width and thickness is measured after thesample is released from the sample holder. The impedance readings aretaken after the values stabilize without significant change.

b. At Defined Relative Humidities

The relative humidity (“R.H.”) is determined by using saturated saltsolutions. Polymer samples are is placed in a sample holder positionedabove the salt solution. Adjustment of a specific humidity requires theuse of a closed container. The following saturated salt solution areused for producing the R.H. at 80° C. (ASTM, E104-02): Salt NaCl NaBrMgCl₂ R.H. @ 80° C. 74% 51% 26%

With reference to FIG. 1, a comparison of the specific conductivitiesfor example 1, example 2, and example 3 are provided. Example 1 is acomparative example that possesses sulfonation only on the main chain,the block copolymer of example 2 has sulfonation on the side chain, andexample 3 has sulfonation on both the side and main chain. Both examples2 and 3 have higher specific conductivities than comparative example 1,with the polymer from example 3 being the highest. With reference toFIG. 2, plots comparing the specific conductivities as a function ofrelative humidity for a polymer having formula 20 to a block copolymerfrom example 2 are provided. Again, the conductivity of the blockcopolymer of the present invention with sulfonation on the side chain isobserved to be higher.

Table 1 provides a comparison of the physical properties of polymerscontaining phosphonic acid groups versus sulfonic acid groups.Significantly, the block copolymers that have phosphonic acid groupshave significantly higher conductivities although the water uptake ismuch lower than polymers with sulfonic acid groups. TABLE 1 Physicalproperties of block copolymers. IEC Water uptake % ConductivityConductivity (elemental (room (80° C., 26% (80° C., liquid analyis) IEC(titrated) temperature, R.H.) water) Acid group meq/g Meq/g liquidwater) S/cm S/cm Phosponic 1.7 0.16 7 0.0003 0.09 Sulfonic 1.7 700.00009

EXAMPLE 1 Synthesis of Block Copolymer Having Formula 21

A) Preparation of Block Having Formula 22

Bis-(4-hydroxyphenyl)-sulfone (30.00 g, 0.1199 mol),4,4′-Difluorobenzophenone (32.85 g, 0.1505 mol), potassium carbonate(35.67 g, 0.256 mol), 170 ml anhydrous N-methyl-pyrrolidone and 75 mlanhydrous benzene are added to a 500 ml flask equipped with a Dean-Starktrap, a reflux condenser and a nitrogen inlet. The mixture is refluxedat 140° C. for 3 hour under nitrogen atmosphere. The benzene is removed,and the mixture is heated for an additional 18 hour at 180° C. Themixture is filtered and diluted with 150 ml NMP. The solution is pouredinto 3 l methanol under vigorous stirring. The precipitated solid iswashed with 1 l methanol, 1 l D. I. water (70-80° C.), 1 l methanol anddried at 100° C. in vacuum. The yield is 46 g (88%).

B) Preparation of Multiblock Copolymer Having Formula 21 (Calc. IEC 1.8meq/g)

The polymer block having formula 22 (4.00 g, ca. 0.001 mol),hydoquinone-2-potassium sulfonate (5.03 g, 0.022 mol),4,4′-Difluorobenzophenon (4.64 g, 0.021 mol), potassium carbonate (6.1g, 0.044 mol), 90 ml anhydrous and 40 ml anhydrous benzene are added toa 250 ml flask equipped with a Dean-Stark trap, reflux condenser and anitrogen inlet. The mixture is refluxed at 140° C. for 3 hours undernitrogen. The benzene is removed and the mixture is heated for anadditional 21 hours at 180° C. The mixture is filtered and diluted withDMSO. The solution is then poured into 3 1 methanol under vigorousstirring. The precipitated solid is washed with methanol and dried at100° C. in vacuum. The yield is 10 g (79%). Membranes having a thicknessof about 50 μm are cast from a DMSO solution and dried at 60° C. An IECof 1.7 meq/g is determined by titration.

EXAMPLE 2 Synthesis of Block Copolymer Having Formula 23

A) Preparation of Polymer Block Having Formula 24

Potassium carbonate (214.3 g, 1.55 mol),2,2-Bis-(4-hydroxy-phenyl)-propane (176.96 g, 0.775 mol),1,3-Bis-(4-fluorbenzoyl)benzene (154.72 g, 0.480 mol), 1.5 l anhydrousN-methyl-pyrrolidone and 200 ml anhydrous cyclohexene are added to a 2 lflask equipped with a Dean-Stark trap, a reflux condenser and a nitrogeninlet. The mixture is refluxed at 140° C. for 3 hour under nitrogen.Benzene is removed, and the mixture is heated for further 24 hour at180° C. The mixture is filtered and diluted with 150 ml NMP. Thesolution is poured into 10 l methanol under vigorous stirring. Theprecipitated solid is washed with 2 l methanol, 2 l D. I. water (70-80°C.), 1 l methanol and dried at 100° C. in vacuum. The yield is 200 g(66%).

B) Preparation of Multiblock Copolymer Having Formula 23 (Calc. IEC=1.7meq/g)

Polymer block having formula 24 (1.129 g, ca. 0.0005 mol), thesulfonated THPE side chain monomer having formula 25 (2.602 g, 0.0035mol), 4,4′-difluorobenzophenon (0.869 g, 0.0040 mol), potassiumcarbonate (1.0 g, 0.07 mol), 25 ml anhydrous, and 25 ml anhydrousbenzene are added to a 100 ml flask equipped with a Dean-Stark trap,reflux condenser and a nitrogen inlet. The mixture is refluxed at 140°C. for 3 hour under nitrogen. The benzene is removed and the mixture isheated for 4 hour at 200° C. The mixture is filtered, diluted with DMSOand the solution is poured into an excessive amount of methanol undervigorous stirring. The precipitated solid is washed with methanol anddried at 100° C. in vacuum. The yield is 4.5 g (90%). Membranes having athickness of about 70 μm are cast from a DMSO solution and dried at 60°C. An IEC of 1.5 meq/g is determined by titration.

EXAMPLE 3 Synthesis of Multiblock Copolymer Having Formula 26 (Calc.IEC=2.7 meq/g)

Polymer block having formula 24 (from Example 2A)) (1.92 g, ca. 0.0008mol), the sulfonated THPE side chain monomer having formula 25 (2.433 g,0.0033 mol), 4,4′-difluoro-3,3′-di(potassium sulfonate)-benzophenon(1.863 g, 0.0041 mol), potassium carbonate (0.93 g, 0.067 mol), 25 mlanhydrous DMSO and 25 ml anhydrous benzene are added to a 100 ml flaskequipped with a Dean-Stark trap, reflux condenser and a nitrogen inlet.The mixture is refluxed at 140° C. for 3 hour under nitrogen. Thebenzene is removed and the mixture is heated for an additional 4 hoursat 200° C. The mixture is filtered, diluted with DMSO and the solutionis poured in an excessive amount of methanol under vigorous stirring.The precipitated solid is washed with methanol and dried at 100° C. invacuum. The yield is 6 g (85%). Membranes having a thickness of about 40μm are cast from a DMSO solution and dried at 60° C. An IEC of 2.5 meq/gis determined by titration.

EXAMPLE 4 Synthesis of Multiblock Copolymer Having Formula 27

A) Synthesis of (4-bromophenyl)(4′-fluorophenyl)methanone (Formula 28)

4-Fluorobenzoyl chloride (238 g, 1.5 mol) is added under an atmosphereof nitrogen over a period of 1 hour to a suspension of anhydrousaluminium chloride (224 g, 1.68 mol) and 700 ml bromobenzene whilemaintaining the temperature below 30° C. After the addition is complete,the solution is heated at 90° C. for 3 hour. The reaction solution isadded to 500 g crushed ice. The mixture is allowed to warm to roomtemperature and the water phase is extracted with dichloromethane (3times with 200 ml). The organic extracts are combined, washed with water(200 ml), saturated sodium hydrogene carbonate solution (200 ml), water(200 ml), dried over sodium sulphate, filtered, and evaporated todryness. The residue is crystallized twice from petroleum ether (b.p.:36-80° C.) to obtain a pale yellow powder. The yield is 240-278 g(57-67%).

B) Synthesis of diethyl 4-(4-fluorobenzoyl)phenylphosphonate (Formula29)

(4-Bromophenyl)(4′-fluorophenyl)methanone (formula 28) (400 g, 1.43 mol)from Example 4A and anhydrous nickel bromide (35 g, 0.16 mol) are heatedto 160° C. under an atmosphere of nitrogen. A green-blue colored melt isobtained. Then triethyl phosphite (304 g, 1.83 mol) is added over aperiod of 1 hour while maintaining the temperature between 160 and 165°C. The mixture is stirred at this temperature for an additional hour.Distillation of the mixture gave a pale yellow oil, b.p. 187-188°C./10-2 mbar. The yield is 304-326 g (63-68%).

C) Synthesis of potassium 4-(4-fluorobenzoyl)phenylphosphonate (Formula30)

Diethyl 4-(4-fluorobenzoyl)phenylphosphonate (formula 29) (80 g, 0.24mol) in 100 ml hydrobromic acid (48%) is heated under vigorous stirringfor 60 hour at reflux. Additionally at regular intervals 300 mlhydrobromic acide (48%) is added. The generated white solid is filteredoff, washed with water (3 times with 300 ml water) and dried. The yieldof the released phosphonic acid is 66-69 g (89-91%). The potassium saltof the phosphonic acid is established by boiling a aqueous solution(15-30 wt %) of the phosphonic acid with equimolar quantities ofpotassium hydroxide until a clear solution is obtained. Then thesolution is evaporated to dryness and the resulting salt is used withoutfurther purification.

D) Synthesis of potassium4-(4-{3-(di(4-hydroxyphenyl)ethyl)phenoxy}benzoyl)phenylphosphonate(Formula 31)

1,1,1-Tris-(4-hydroxyphenyl)-ethane (551 g, 1.80 mol) and potassiumcarbonate (74 g, 0.54 mol) are added to 1.5 l anhydrous dimethylsulphoxide (DMSO) under an atmosphere of nitrogen. The temperature israised to 120° C. Then the compound having formula 30 (127 g, 0.36 mol)is added to 600 ml anhydrous DMSO at 100° C. and distilled water isadded until a clear solution is obtained. This solution is added over aperiod of 4-5 hour while maintaining the temperature between 120 and125° C. After the addition is complete the mixture is stirred at thistemperature for 14-15 hour. Then the solvent is distilled off and theresulting residue is added to a mixture of 500 ml distilled water and400 ml ethyl acetate. The water phase is neutralized with hydrochlorideacid and then extracted with ethyl acetate (5×'s 300 ml). The combinedorganic extracts are washed once with water. Afterwards the combinedwater phases are evaporated to dryness and the residue is extracted withmethanol (3×'s 100 ml). The product is purified by adding the combinedmethanol extracts to 1.5 l diethyl ether, followed by twicerecrystallization of the precipitated solid in a mixture of distilledwater/ethanol. The yield is 53-72 g (23-31%).

E) Synthesis of Side Chain Phosphonated Multiblock Having Formula 27

The OH-terminated polymer block having formula 24 (2.4009 g, 0.469mmol), 4,4′-Difluorobenzophenone (0.6146 g, 2.817 mmol), side chainphosphonated monomer having formula 31 (1.5087 g, 2.347 mmol), andpotassium carbonate (0.8565 g, 6.200 mmol) are dissolved in a mixture of24 ml anhydrous 1,3-Dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone(“DMPU”) and 25 ml anhydrous benzene in a 100 ml flask equipped with aDean-Stark trap and reflux condenser. Then the mixture is refluxed at140° C. for 3 hour under nitrogen. Benzene is removed and the mixture isheated for 2.5 hour at 180° C. The highly viscous mixture is poured intoa mixture of 500 ml distilled water and 50 ml hydrochloric acid (37%).The precipitated solid is washed with 21 distilled water. The yield is4.03 g (91%). Polymer prepared in DMPU can be cast into membranes fromDMAC solution. Membranes are transparent but brittle: No determinationof conductivity, water uptake etc.

EXAMPLE 5 Synthesis of Block Copolymer Having Formula 32

A) Synthesis of F-Terminated Block Copolymer Having Formula 33:

2,2-bis-(4-hydroxyphenyl)propane (44.7108 g, 0.196 mol),1,3-bis-(4-fluorbenzoyl)benzene (70.0150 g, 0.217 mol) and potassiumcarbonate (54.14 g, 0.392 mol) are dissolved in a mixture of 300 mlanhydrous N-methyl-pyrrolidone (NMP) and 75 ml anhydrous benzene in a500 ml flask equipped with a Dean-Stark trap and reflux condenser. Themixture is refluxed at 140° C. for 4 hour under nitrogen. Benzene isremoved, and the mixture is heated for further 24 hour at 180° C. Themixture is filtered, diluted with 150 ml NMP and 150 ml tetrahydrofuranand the solution poured into 3 l methanol. The precipitated solid iswashed with 1 l methanol, 1 l distilled water (70-80° C.), 1 l methanoland dried. The yield is 99 g (93%).B) Bromination of F-Terminated Block Having Formula 34:

Bromine (316 g, 1.98 mol) is dissolved in 200 ml chloroform and added toa solution of the F-terminated block polymer having formula 33 (106 g)in 1.2 l chloroform at room temperature over a period of 4 hour. Thenthe mixture is slowly raised (2 hours) to refluxing temperature andboiled for 15 hour at reflux. The mixture is allowed to cool andprecipitated in methanol. The solid is washed twice with methanol anddried. The yield is 100 g.C) Synthesis of Brominated Block Copolymer Having Formula 35:

Brominated block having formula 34 (22.0090 g, 1.95 mmol),1,3-bis-(4-fluorbenzoyl)benzene (3.7719 g, 11.71 mmol),2,2-bis-(4-hydroxyphenyl)-propane (3.1168 g, 13.65 mmol) and potassiumcarbonate (4.152 g, 30.04 mmol) are dissolved in a mixture of 110 mlanhydrous N-methyl-pyrrolidone (“NMP”) and 40 ml anhydrous benzene in a250 ml flask equipped with a Dean-Stark trap and reflux condenser. Themixture is refluxed at 140° C. for 4 hour under nitrogen. Benzene isremoved, further 30 ml NMP is added and the mixture is heated for 24hour at 180° C. The mixture is filtered, diluted with 300 ml NMP and 350ml tetrahydrofuran and the solution poured into 4 1 methanol. Theprecipitated solid is washed with 1 l methanol, 1 l distilled water(70-80° C.), 1 l methanol and dried. The yield is 27 g (95%).D) Synthesis of Phosphonated Block Copolymer Having Formula 36:

Brominated block copolymer having formula 35 (4.0 g) and anhydrousnickel bromide (0.33 g) is added to a mixture of 70 ml anhydrousdiethylene glycol dimethyl ether and 20 ml N-methyl-pyrrolidone under anatmosphere of nitrogen. The temperature is raised to 155° C. andtriethyl phosphite (6.0 g) is added over a period of 20 minutes at150-15° C. After 30 minutes further anhydrous nickel bromide (0.33 g) isadded and the solution is stirred for 4 hour. Then the solution isallowed to cool somewhat and poured into 1 l distilled water. Theprecipitated solid is washed with 500 ml methanol, 500 ml distilledwater (70-80° C.), 500 ml methanol and dried. The yield is 3.8 g.

E) Conversion to Phosphonated Polymer Having Formula 32—Generation ofPO(OH)₂-Groups:

Addition of phosphonated block copolymer having formula 36 (3.3 g) to150 ml anhydrous dichloromethane under an atmosphere of nitrogenresulted a gel-like mass. A clear solution is obtained by addingbromotrimethylsilane (4.6 g) over a period of 20 minutes at roomtemperature to the mixture. After the addition is complete, the solutionis stirred for 40 minutes at room temperature and heated for 1 hour atreflux. Then the solution is allowed to cool somewhat and poured into 1l methanol. The precipitated solid is washed twice with methanol anddried. The yield is 2.9 g. Polymer can be cast into membranes from DMACsolution. Such membranes are transparent and not brittle. Thephosphonated polymer having formula 30 is observed to have a wateruptake in liquid water at RT 7% and a proton conductivity of 0.09 S/cmat 30° C. in water and 0.0003 S/cm at 80° C. and 26% R.H.

While embodiments of the invention have been illustrated and described,it is not intended that these embodiments illustrate and describe allpossible forms of the invention. Rather, the words used in thespecification are words of description rather than limitation, and it isunderstood that various changes may be made without departing from thespirit and scope of the invention.

1. A block copolymer for use as a solid polymer electrolyte, the blockcopolymer comprising a polymer having formula 1:(A_(m)B_(n))_(p)   1 wherein A is a first polymer segment that isrepeated m times to form first polymer block A_(m); B is a secondpolymer segment that is repeated n times to form second polymer blockB_(n), the second polymer block having a main polymer chain and one ormore side chains extending from the main polymer chain, wherein the oneor more side chains include at least one substituent for protontransfer; m, n are each independently an integer from 1 to 200; and p isan integer from 1 to 20; wherein first polymer block A_(n) is bonded tosecond polymer block B_(m) and the block copolymer is formable into anion-conductive membrane.
 2. The block copolymer of claim 1 wherein theat least one substituent for proton transfer comprises an acidicsubstituent or a salt of a conjugate base thereof.
 3. The blockcopolymer of claim 1 wherein the first polymer block A_(m) ishydrophobic and the second polymer block B_(n) is hyrdrophilic.
 4. Theblock copolymer of claim 3 wherein the block copolymer has a micro-phaseseparated morphology.
 5. The block copolymer of claim 4 wherein themicro-phase separated morphology comprise spheres, cylinders, lamellae,ordered bi-continuous double diamond structures, disordered bicontinuousmorphologies, and combinations thereof.
 6. The block copolymer of claim1 wherein the first block has a molecular weight from about 5×10² toabout 5×10⁵ (g/mol) and the second polymer block has a molecular weightfrom about 5×10² to about 5×10⁵ (g/mol).
 7. The block copolymer of claim1 wherein the at least one substituent for proton transfer is selectedfrom the group consisting of —SO₃H, —SO₃ ⁻M⁺, —COOH, —COO⁻M⁺, —PO₃H₂,—PO₃H⁻M⁺, —PO₃ ²⁻M₂ ⁺, —PO₃ ^(2'1)M²⁺, and combinations thereof, whereinM is an alkali or alkaline-earth metal, ammonium, or alkylammonium. 8.The block copolymer of claim 1, wherein B is described by formula 2:

wherein: Y¹ is —O—, —S—, —CO—, —SO₂—, —C(CH₃)₂—, —C(CF₃)₂—, —P(O)(T¹)-,—C(CH₃)(T¹)-, —P(O)(R⁴)—, diphenyl methylene, diphenyl silicon,fluorenyl, an alkylene, a bond directly to the next aromatic ring, or

R¹, R², and R³ are each independently H, C₁₋₁₀ alkyl, C₆₋₁₈ s aryl,C₆₋₁₈ aralkyl, SO₃H, —SO₃ ⁻M⁺, —COOH, —COO⁻M⁺, —PO₃H₂, —PO₃H⁻M⁺, —PO₃ ²⁻M₂ ⁺, or —PO₃ ²⁻M²⁺; R⁴ is H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl, or C₆₋₁₈aralkyl; T¹ is H or a moiety having at least one substituent for protontransfer; and i is an integer from 1 to 6; with the proviso that wheni>1, the Y¹ between sequential aromatic rings are the same or different;the T¹ on sequential aromatic rings are the same or different; the R¹,R², and R³ on sequential aromatic rings are the same or different; andT¹ is a moiety having at least one substituent for proton transfer forat least one aromatic ring in B.
 9. The block copolymer of claim 8wherein T¹ is given by formula 3:

Y² is —O—, —S—, —CO—, —SO₂—, —C(CH₃)₂—, —C(CF₃)₂—, —P(O)(R⁴)—, diphenylmethylene, diphenyl silicon, fluorenyl, an alkylene, or a bond directlyto the next aromatic ring; R⁴ is H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl, or C₆₋₁₈aralkyl; R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², and R¹³ are eachindependently H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl, C₆₋₁₈ aralkyl, SO₃H, —SO₃ ⁻M⁺,—COOH, —COO⁻M⁺, —PO₃H₂, —PO₃H⁻M⁺, —PO₃ ²⁻M₂ ⁺, or —PO₃ ²⁻M²⁺; M is ametal, ammonium, or alkylamonium; and j is an integer from 1 to 30; withthe proviso that when j>1, the Y² between sequential aromatic rings arethe same or different; the R⁵, R⁶, R⁷, R⁸, and R⁹ on sequential aromaticrings are the same or different, wherein at least one of R⁵, R⁶, R⁷, R⁸,R⁹, R¹⁰, R¹¹, R¹², and R¹³ is —SO₃H, —SO₃ ⁻M₊, —COOH, —COO⁻M⁺, —PO₃H₂,—PO₃H⁻M⁺, —PO₃ ²⁻M₂ ⁺, or —PO₃ ²⁻M²⁺.
 10. The block copolymer of claim 8wherein B comprises a component selected from the group consisting ofsegments having formulae 5 to 12, and salts thereof:


11. The block copolymer of claim 8 wherein A is described by formula 4:

wherein: Y₃ is —O—, —S—, —CO—, —SO₂—, —C(CH₃)₂—, —C(CF₃)₂—, —P(O)(T¹)-,—C(CH₃)(T¹)-, —P(O)(R⁴)—, diphenyl methylene, diphenyl silicon,fluorenyl, an alkylene, a bond directly to the next aromatic ring, or

R⁴ is H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl, or C₆₋₁₈ aralkyl; R¹⁴, R¹⁵, R¹⁶, andR¹⁷ are each independently H, C₁₋₁₈ alkyl, C₆₋₁₈ aryl, or C₆₋₁₈ aralkyl;k is an integer from 1 to 6; with the proviso that when k>1, the Y³between sequential aromatic rings are the same or different, and theR¹⁴, R¹⁵, R¹⁶, and R¹⁷ on sequential aromatic rings are the same ordifferent.
 12. The block co-polymer of claim 11 wherein A comprises acomponent selected from the group consisting of polymer segments havingformulae 13 to 16; and salts thereof:


13. An ion conductive membrane made from the block copolymer of claim11.
 14. The ion conductive membrane of claim 13 made by a methodcomprising: a) synthesizing an end-functionalized first polymer blockhaving formula 18:

wherein Z¹ and Z² are each independently —H, —SH, —S(O)N(R¹⁸)₂, F, Cl,Br, I, —NO₂, or —OH; and R¹⁸ is H, C₁₋₁₀ alkyl, cycloalkyl, C₆₋₁₈ aryl,or C₆₋₁₈ aralkyl; b) synthesizing an end functionalized second polymerblock having formula 19:

wherein Z₃ and Z₄ are each independently H, —SH, —S(O)N(R¹⁸)₂, F, Cl,Br, I, —NO₂, or —OH; and c) reacting the products of steps a) and b) toform the block copolymer.
 15. The ion conductive membrane of claim 13made by a method comprising: a) synthesizing an end-functionalizedpolymer block having formula 19:

wherein Z¹ and Z² are each independently —H, —SH, —S(O)N(R¹⁸)₂, F, Cl,Br, I, —NO₂, or —OH; and R¹⁸ is H, C₁₋₁₀ alkyl, cycloalkyl, C₆₋₁₈ aryl,or C₆₋₁₈ aralkyl; b) reacting the polymer block having formula 19 withone or more monomers that polymerize into a block having formula 2:

to form the block copolymer having formula
 1. 16. The ion conductivemembrane of claim 15 wherein the method further comprises: a)transforming the acid groups of the block copolymer to acid halidegroups to form a modified block copolymer, b) casting a film from asolution of the modified block copolymer of step a) onto a substrate;and c) transforming the acid halide groups into the acid groups to formthe ion conductive membrane.
 17. The ion conductive membrane of claim 13made by a method comprising: a) synthesizing an end-functionalizedpolymer block having formula 18:

wherein Z¹ and Z² are each independently —H, —SH, —S(O)N(R¹⁸)₂, F, Cl,Br, I, —NO₂, or —OH; and R¹⁸ is H, C₁₋₁₀ alkyl, cycloalkyl, C₆₋₁₈ aryl,or C₆₋₁₈ aralkyl; b) reacting the polymer block having formula 18 withone or more monomers that polymerize into a block having formula 4:

to form the block copolymer having formula
 1. 18. A block copolymer foruse as a solid polymer electrolyte, the block copolymer comprising apolymer having formula 1:(A_(m)B_(n))_(p)   1 wherein A is a first polymer segment described byformula 4:

B is a second polymer segment described by formula 2:

Y¹ and Y³ are each independently —O—, —S—, —CO—, —SO₂—, —C(CH₃)₂—,—C(CF₃)₂—, —P(O)(T¹)-, —C(CH₃)(T¹)-, —P(O)(R⁴)—, diphenyl methylene,diphenyl silicon, fluorenyl, an alkylene, a bond directly to the nextaromatic ring, or

R¹, R², and R³ are each independently H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl, C₆₋₁₈aralkyl, —SO₃H, —SO₃ ⁻M⁺, —COOH, —COO⁻M+, —PO₃H₂, —PO₃H⁻M⁺, —PO₃ ²⁻M₂ ⁺,or —PO₃ ²⁻M²⁺; R⁴ is H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl, or C₆₋₁₈ aralkyl; M isa metal, ammonium, or alkylammonium; R¹⁴, R¹⁵, R¹⁶, and R₁₇ are eachindependently H, C₁₋₁₈ alkyl, C₆₋₁₈ aryl, or C₆₋₁₈ aralkyl; T¹ is H or amoiety having at least one substituent for proton transfer; m, n areeach independently an integer from 1 to 200; and p is an integer from 1to 20; i is an integer from 1 to 6; k is an integer from 1 to 6; withthe proviso that when i>1, the Y¹ between sequential aromatic rings arethe same or different; the T¹ on sequential aromatic rings are the sameor different and R¹, R², and R³ on sequential aromatic rings are thesame or different; and when k>1, the Y³ between sequential aromaticrings are the same or different and the R¹⁴, R¹⁵, R¹⁶, and R¹⁷ onsequential aromatic rings are the same or different; wherein for atleast one aromatic ring in formula 2, either T¹ is not H or one of R¹,R², and R³ is —SO₃H, —SO³⁻M⁺, —COOH, —COO⁻M⁺, —PO₃H₂, —PO₃H⁻M⁺, —PO₃ ²M₂⁺, or —PO₃ ²⁻M²⁺.
 19. The block copolymer of claim 18 wherein T¹ isgiven by formula 3:

Y² is —O—, —S—, —CO—, —SO₂—, —C(CH₃)₂—, —C(CF₃)₂—, —P(O)(R⁴)—, diphenylmethylene, diphenyl silicon, fluorenyl, an alkylene, or a bond directlyto the next aromatic ring; R⁴ is H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl, or C₆₋₁₈aralkyl; R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², and R¹³ are eachindependently H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl, C₆₋₁₈ aralkyl, SO₃H, —SO₃ ⁻M⁺,—COOH, —COO⁻M⁺, —PO₃H₂, —PO₃H⁻M⁺, —PO₃ ²⁻M₂ ⁺, or —PO₃ ²⁻M²⁺; M is ametal, ammonium, or alkylammonium; and j is an integer from 1 to 30,with the proviso that when j>1, the Y² between sequential aromatic ringsare the same or different and the R⁵, R⁶, R⁷, R⁸, and R⁹ on sequentialaromatic rings are the same or different; wherein at least one of R⁵,R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², and R¹³ is —SO₃H, —SO₃ ⁻M⁺, —COOH,—COO⁻M⁺, —PO₃H₂, —PO₃H⁻M⁺, —PO₃ ²⁻M₂₊, or —PO₃ ²⁻M²⁺.
 20. The blockcopolymer of claim 18 wherein R¹, R², and R³ are each independently H,—PO₃H₂, —PO₃H⁻M⁺, —PO₃ ²⁻M₂ ⁺, or —PO₃ ²⁻M²+; and T¹ is H.
 21. The blockcopolymer of claim 18 wherein R¹, R², and R³ are each independently H,—PO₃H₂, —PO₃H⁻M⁺, —PO₃ ²⁻M₂ ⁺, or —PO₃ ²⁻M²⁺; and T¹ is H.
 22. An ionconductive membrane made from the block copolymer of claim
 16. 23. Ablock copolymer having formula 1:(A_(m)B_(n))_(p)   1 wherein: A is a polymer segment described byformula 17:

wherein: m, n are each independently an integer from 1 to 200; and p isan integer from 1 to 20; R¹⁹, R²⁰R²¹, R₂₂, R²³, R₂₄, R₂₅, R²⁶, R²⁷, R²⁸,R²⁹, R³⁰, R³¹, R₃₂, R³³, and R³⁴ are M₂ ⁺, or —PO₃ ²⁻M²⁺; M is a metal,ammonium, or alkylammonium; and B is a second polymer segment.
 24. Theblock copolymer of claim 23 wherein B is described by formula 4:

wherein: Y³ is —O—, —S—, —CO—, —SO₂—, —C(CH₃)₂—, —C(CF₃)₂—, —P(O)(T¹)-,—C(CH₃)(T¹)-, —P(O)(R⁴)—, diphenyl methylene, diphenyl silicon,fluorenyl, an alkylene, a bond directly to the next aromatic ring, or

R⁴ is H, C₁₋₁₀ alkyl, C₆₋₁₈ aryl, or C₆₋₁₈ aralkyl; R¹⁴, R¹⁵, R¹⁶, andR¹⁷ are each independently H, C₁₋₁₈ alkyl, C₆₋₁₈ aryl, or C₆₋₁₈ aralkyl;k is an integer from 1 to 4; with the proviso that when k>1, the Y³between sequential aromatic rings are the same or different and the R¹⁴,R¹⁵, R¹⁶, and R¹⁷ on sequential aromatic rings are the same ordifferent.